AVS Forum banner

Status
Not open for further replies.
1 - 3 of 3 Posts

·
Registered
Joined
·
13,049 Posts
Discussion Starter · #1 ·
I currently have a LCD pj rated at 1100 lumens. This is a native 4:3 pj with a res of 800x600 that I watch on a 87" diag 4:3 screen.


When I watch DVDs in 2.35:1 format on my 4:3 screen, I lose approximately 40% of the screen's viewable area because of the difference in aspect ratio.


So my main question is this - am I correct to assume that instead of getting 1100 lumens, I'm actually getting about 40% less lumens - or about 660? In other words, for the portion of the panel that is not used due to aspect ratio vs. native panel, you lose the light output from the unused portion of the panel. Is this a correct assumption?


Likewise if I have a InFocus 7200 rated at 1000 lumens, and I watch a 2.35:1 movie on a 16:9 screen, I lose about 15% (I think) of the picture because of 2.35:1 vs 16:9. So in that case I actual lose 15% of the 1000 lumens as well. Is this correct?


Thanks!
 

·
Registered
Joined
·
17,711 Posts
yes and no.


Yes, showing a black image will output less light, so the black borders are loosing lumens. But that is not important. The brightness of the part of the screen that is white will be greater on a projector that has more lumens then one that has less
 

·
Registered
Joined
·
1,195 Posts
1 - 1.33/2.35 = .43 loss

1 - 1.78/2.35 = .24 loss


So, yes and no, you're a little low on the 16:9 > 2.35:1 case.


I add this since it seems to come up in these sorts of threads:


Ft Lamberts ( how bright the picture appears ) = lumens * screen_gain / Sq_ft


If you don't change anything (no zooming) when you go from using the whole panel to using part of the panel the Ft Lamberts of the picture stays the same. This is because the real estate size of the picture (Sq_ft) drops proportional to the lumen loss.


But you are "throwing" less lumens into the room - so it might not be as easy to read a book. This is why some people use anamorphic lenses - more pixels and a brighter picture.


Edit: for spelling
 
1 - 3 of 3 Posts
Status
Not open for further replies.
Top